The incidence of acquired immunodeficiency syndrome (AIDS) in children is increasing, the source of infection usually being the mother. Approximately 75% children with HIV infection are offspring of IV drug abuser parent(s). Diagnosis of HIV infection in newborns and asymptomatic infants is, however, a problem because all infants born to HIV seropositive woemen have passively transferred maternal antibodies which may persist up to and even beyond 15 months of age. Infected and uninfected infants thus cannot be distingushed on the basis of routine immunological or serological testing. A hypothesis of this proposal is that HIV infected infants have HIV-specific B & T cells whose properties can be exploited in-vitro to enable the distrinction between infected and uninfected infants. Novel tests of HIV-specific immunity (in- vitro HIV antibody synthesis, antibody clonotype pattern and HIV antigen specific lymphoproliferation) will be coupled with tests for the polymerase chain reaction, HIV viral cultures and HIV antigen in a multi-test diagnostic approach to this probolem. HIV infection in the pediatric population results in a wide spectrum of clinical and immunologic distrubances, ranging from asymptomatic to severely ill and form immunocompetent to severely immunocompromised status. Main target systems attacked by HIV are the immune system and the nervous system. A second hypothesis to be tested is that rapidity of disease progression is closely linked to initial clinical presentation and laboratory findings. Systematic investigations of the neurological and immunological status, HIV-specific immunity and HIV antigen levels will provide insights into the clinical, virologic and immunologic spectrum in this disease. An important feature of this investigation will be data management. The ability of diagnosing HIV infection in infancy and an understanding of the mechanisms involved in disease progression should bring us closer to developing and monitoring therapeutic strategies against this deadly disease.